#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>


int main()
{
	char pan[8][9];
	int result = 1;
	for (int i = 0; i < 8; i++) {
		scanf("%s", pan);
	}
	for (int m = 0; m < 8; m++) {
		for (int n = 0; n < 8; n++) {
			char a = pan[m][n];
			char b = pan[m][7 - n];
			char c = pan[m][n + 1];
			char d = pan[m][n - 1];

			if (n == 0) {
				if (a == b || a == c)
					result = 0;
			}
			if (n == 7) {
				if (a == b || a == d)
					result = 0;
			}
			else if (a == d || a == c)
				result = 0;
		}
	}
	if (result == 0)
		printf("NO");
	else
		printf("YES");
	return 0;
}
